Yarn treating method and apparatus for knitting machines



July 7, 1964 H. M. STRUB, JR

YARN TREATING METHOD AND APPARATUS FOR KNITTING MACHINES Filed April 2, 1957 INVENTOR: HENRY M- STRUB, d12- w @(M AJJ-A*W ATTORNEYS United States Patent Office dddfifldl Patented July 7, 1964 3,139,741 YARN TREATING METHOD AND APPARATUS FUR KNETTING MACHINES Henry M. fitrub, .l'in, Charlotte, N.C., assignor to The Duplan Corporation, WinstomSalern, N.C., a corporation of Delaware Filed Apr. 2, 1957, Ser. No. 650,293 Claims. (ill. 66-425) This invention relates to a yarn treating apparatus for knitting machines and more especially to an apparatus for applying heat to a running yarn, as the yarn is fed to a knitting machine, for shrinking the yarn prior to it being knitted. This invention is for use with any type of yarn capable of being shrunk by application of heat thereto.

Heretofore, many difiiculties have arisen in the knitting and pre-boarding of ladies circular knit full length stockings due to the great difference required in the diameter of the finished stocking at various portions thereof, such as t .e difference between the diameter at the welt or top, ankle and foot. A large diameter top or welt must be knitted to compensate for the shrinkage of the fabric during the pre-boarding operation and one method of knitting larger welts has been to draw longer or looser stitches during the formation of the welt than the stitches which are drawn during the formation of other portions of the stockings, such as the ankles. Many difficulties have been experienced in knitting loose stitches in the welt without producing a fabric having defects therein such as distorted stitches described as crows feet or hen tracks and difficulties in pre-boarding the stocking have also been encountered since a loosely knit welt fits so loosely on the boarding form that the operator must spend extra time to smooth and position the welt so that it will shrink evenly on the board during the pre-boarding operation. In the pie-boarding operation the hose is subjected to heat and pressure to cause the yarn and hose to shrink to the shape of the boarding form and set the hose in the shape of the board.

An improvement over the above-mentioned method is shown in a Patent No. 2,396,166, issued March 5, 1946 to B. l. Faucette wherein a method of making seamless hosiery is described which includes knitting the welt with regular size stitches of a ure-shrunk yarn and the remaining portion of the hose or stocking of a relatively unshrunk yarn to overcome the disadvantages of loose stitch knitting. stocking is placed on a form board and subjected to the pro-boarding operation where the welt of the stocking will fit the form fairly close and will shrink only a small amount. This method produces a stocking with a satisfactory welt but requires that the welt yarn be pre-shrunk prior to placing it on tr e knitting machine and involves the use of split core contractable cones onto which the yarn is wound so that the yarn may shrink freely during thepre-shrinking operation. This method necessitates the extra handling of the welt yarn before the knitting operation which increases the cost of the welt considerably.

It is the primary object of this invention to provide a method of shrinking a yarn while the yarn is fed to a knitting machine to shrink the yarn prior to knitting which will do away with any treatment to the yarn before placing it on the knitting machine.

It is another object of this invention to provide a yarn heating apparatus associated with a knitting machine and which employs heat adjacent the running yarn to shrink the yarn just prior to knitting and which yarn heating apparatus may be controlled so that various degrees of shrinkage may be obtained in a single end of running yarn. Control of the yarn heating apparatus may be eifected through pattern control means on the knitting machine Following the knitting operation the and may be varied from course to course according to the progress of the knitted article, if desired.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds when taken in connection with the accompanying drawings, in which FIGURE 1 is a side elevation of the upper portion of a circular knitting machine and showing the yarn shrinkmg apparatus applied thereto;

FIGURE 2 is a fragmentary plan view taken substantially along the line 22 in FIGURE 1;

FIGURE 3 is an enlarged fragmentary elevation taken substantially along the line 3-3 in FIGURE 1;

FIGURE 4- is an enlarged fragmentary plan view taken substantially along the line 4--4 in FIGURE 1.

In the drawings and specification the invention has been described as being associated with a circular knitting machine. However, it is to be understood that the yarn shrinking apparatus could be easily adapted for use with a full-fashioned knitting machine although the difi'iculties encountered in full-fashioned knit hosiery, as far as the difference in width between the welt and the ankle portions thereof, are not as great as in circular knit hosiery.

The knitting machine with which the present invention is adapted to operate includes a circular knitting machine it) provided with the usual bed plate 11, a needle cylinder 12 having vertically movable needles therein, not shown, adapted to pick up and knit a yarn Y from a plurality ofyarn feeding fingers 13, only one of which is shown. The yarn feeding finger 13 is adapted to be moved into and out of operative position by a thrust bar 14 the lower end of which is raised by cams on a conventional main pattern drum, not shown. The yarn feeding finger 13 is adapted to operate in the throat of a latch ring 15 movable into and out of knitting position on the knitting machine it The knitting machine it) supports a yarn supply stand or creel 20 adapted to support a plurality of yarn supply bobbins or pirns 21, only one of which is shown, having a supply of the yarn Y wound thereon.

The yarn Y extends upwardly from the pirn 21 and passes adjacent the yarn shrinking apparatus, to be later described, and through a U-shaped yarn guide 25 the upper ends of which are fixed in a support bracket 26. The support bracket 26 is fixed on the upper end of a support post 27 the lower end of which is fixed in the yarn supply stand or creel 29. The yarn Y extends from the guide 25 through a yarn lubricating device indicated broadly at 3%) and which includes a lubricant container or jar 31 supported on a bracket 3?... The upper end of the bracket 32 is fixed on the support bracket 26 and is provided with suitable yarn guides or eyelets 33 and 34 which guide the yarn Y to pass in engagement with the upper end of a suitable wick 36. The lower end of the wick 36 extends into the jar 31 and is adapted to feed, by capillary action, a suitable lubricant to the yarn Y as it is passed over and in contact with the wick 36.

The yarn Y extends from the eyelet 34, of the yarn lubricating device 3t), through a conventional yarn tension device illustrated at 49. The yarn tension device 46 may be regulated, relative to the amount of tension applied to the yarn, by conventional pattern control means on the knitting machine It not shown. The tension device 4%) applies tension to the yarn Y as it passes therefrom and through an eye in the yarn feeding finger 13 and to the hooks of the needles in the needle cylinder 12. The parts heretofore described are conventional parts of a circular knitting machine and although a single yarn Y has been described, it is to be understood that several yarns may be fed to individual yarn feeding fingers 13 and the yarn guiding, lubricating and tensoning devices may be duplicated for each running strand of yarn on the machine.

Although a particular type of knitting apparatus is shown in connection with the present invention, it should be understood that the invention may be equally applicable to other types of knitting machines. The present invention includes a first fixed yarn guide or pigtail 50 spaced above the top of the pirn 12 and through which the yarn Y is passed in its path of travel from the pirn 12 to the yarn feeding fingers 13. The pigtail 50 is suitably secured to the lower end of a brace member or support 51 the upper end of which is fixed on a heater support bracket 52. One end of the heater support bracket 52 surrounds and is fixed on the support post 27 and supports yarn heating means which may be in the form of a contact heater 53 fixed on its outer free end. The contact heater 53 is provided with suitable heating means and temperature controlling means, not shown, for varying the temperature of the heater 53 as desired. I

The yarn Y then extends from the pigtail 5t) and through a first movable pigtail 55 which forms a part of the yarn control means 56 for moving the yarn Y out of and into engagement with the surface of the contact heater 53. The yarn control means 56 includes a vertically extending portion 57 which is oscillatably secured intermediate its ends to the side of the support bracket 52 as by a hinge plate 58 (FIGURE 4). The upper end of the vertical portion 57 has a second movable pigtail 60 adapted to have radial swinging movement with oscillation of the vertical portion 57. The yarn Y then extends from the pigtail 60 and through a fixed pigtail 61 mounted on the upper end of a support stand 62 the lower end of which is fixed on the support bracket 52.

The pigtails 55 and 60 may be moved to cause the yarn Y to contact a greater or lesser length of the contact heater 53 or move the yarn Y out of contact with the heater 53 completely by movement of an arm 65 one end of which is fixed intermediate the ends of the yarn control means 56. The free end of the arm 65 is connected to one end of a Bowden wire 66 (FIGURE 4) as by a collar 67 engaging the arm 65. The arm 65 and the yarn control means 56 are urged in a clockwise direction, in FIGURE 4, by a tension spring 7%) one end of which is fixed on the arm 65 and the other end of which is fixed on the bracket 52.

The opposite end of the Bowdren wire 66 is suitably secured to the vertical arm of a bell crank 70 oscillatably mounted intermediate its ends as at 71 on an upstanding portion 72 of a bracket 73, the inner end of which is fixed on the support post 27. The housing of the Bowden wire 66 is fixed on the support bracket 52 as by a clip 68 and on the bracket 73 by a support stand 69. The horizontal arm of the bell crank70 is engaged by and at times moved by the upper end of a thrust bar 75 mounted for vertical sliding movement in the bracket 73. The lower end of the thrust bar 75 is adapted to engage and be controlled by the conventional main pattern drum of the knitting machine, not shown. With downward movement of the thrust bar 75 the bell crank 70 will be moved in a counterclockwise direction (FIGURE l) and the tension spring 7 0 will pull or move the arm 65 and the movable pigtails 55 and 60 of the yarn control means 56 in a clockwise direction, in FIGURE 4, to move the yarn Y so that it contacts a shorter surface of the heater 53 or is moved completely out of contact with the heater 53, depending upon the amount of downward movement of the thrust bar 75. Upward movement of the thrust bar 75 may be effected by suitable cams on the main pattern drum to swing the yarn control means 56 in a counterclockwise direction (FIGURE 4) and move the yarn Y into engagement with the heater 53 or so that the yarn Y contacts a greater length of the surface of the heater 53. Although mechanical means are shown for moving the yarn control means 56, it is to be understood that electrical, hydraulic or pneumatic means may be employed to control contact of the yarn Y with the heater 53.

In knitting the top or welt of a stocking, such as a ladys fine gauge seamless circular knit hose on the knitting machine ]lti, the unshrunk yarn Y is drawn off of the pirn 21 and guided to contact the heater 53 by the guiding pigtails and and shrink the yarn as it is passed over the heater 53 to the degree or percentage desired in the finished product. The amount of shrinkage obtainable in the yarn Y will depend upon the amount of heat transmitted to the running yarn by the heater 53 and may be varied by either varying the amount of current to the heating elements, not shown, in the heater 53 or by varying the length of surface of the heater 53 contacted by the running yarn Y by slight movement of the pigtails 55 and 69 through vertical movement of the thrust bar 75. It will be noted that the yarn Y is shrunk at a position before any tension is applied to the running yarn Y so that the yarn is free to shrink.

Although a contact type heater 53 is shown in the drawings, it is to be understood that there are other types of heaters which may be employed such as radiant type heaters wherein the yarn would pass through a hollow heated tube. Obviously, the temperature of the contact heater 53 will depend upon the length or" the heated surface contacted by the yarn, the denier of the yarn, and the speed at which the yarn passes over the heater 53 at it is fed to the needles of the knitting machine.

For example, it has been found that a forty (40) denier nylon yarn being fed to a knitting machine at the rate of one hundred and ninety-eight (198) yards per minute while contacting a heater for nine (9) inches heated to four hundred and eighty-five (485) degrees Fahrenheit will shrink seven and seven tenths (7.7) percent before being knit. The yarn shrunk according to the above example would be used to knit the welt of the stocking so that the welt will be additionally shrunk only a small amount, approximately two and three tenths (2.3) percent, on the form during the pro-boarding operation.

The yarn shrinking apparatus of this invention is not restricted to use with the welt yarn only and may be used to shrink any desired portion of the finer denier yarns usually used in the leg of the stocking by reducing the temperature of the heater 53 or by reducing the length of contact of the yarn with the heater 53 through movement of the movable pigtails 55 and 60. Although the yarn shrinking heater 53 is shown as being contacted before the tension device 40, the heater 53 may contact the running yarn Y at any point prior to knitting.

If it is found that the heat, applied by the heater 53 to shrink the yarn, has taken away or evaporated a portion, of any lubricant present on the yarn Y, or in order to add additional lubricant or size to the yarn to facilitate easier knitting thereof, theyarn may be passed through the lubricating means 30 to apply a lubricant or size thereto.

It is thus seen that there has been provided a yarn heating attachment for knitting machines for selectively shrinking any portion of the yarn to the desired percentage of shrinkage prior to forming a fabric from said yarn. A simple control mechanism controlled by the pattern mechanism of the knitting machine has also been provided for selectively moving the running yarn into and out of engagement with said heating means as well as for varying the length of time the yarn contacts the heating means. Although the specific example given specifies nylon yarn other types of yarn may be used, the only restriction being that they be capable of being shrunk by heat.

In the drawings and specification there has been set forth a preferred embodiment of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined in the claims.

I claim:

1. A yarn shrinking apparatus for a knitting machine having a yarn supply, stitch forming means, yarn guiding means for directing a yarn from said yarn supply to said stitch forming means, and yarn tension means between said supply means and said stitch forming means, said shrinking apparatus comprising yarn heating means disposed adjacent the path of the running yarn and between said yarn supply means and said yarn tension means, and control means operable by said knitting machine to at times render said yarn heating means operative thereby shrinking the running yarn and at other times to render said yarn heating means inoperative.

2. In a knitting machine having a yarn supply, stitch forming means, a yarn feed finger, and yarn guiding means for directing a yarn from said yarn supply to said feed finger, the combination therewith of a yarn shrinking apparatus comprising yarn heating means adjacent the path of the running yarn, a first fixed yarn guiding element engaging said yarn prior to said yarn heating means, a second fixed yarn guiding element engaging the running yarn subsequent to said yarn heating means, a first movable yarn guiding element engaging the running yarn subsequent to said first fixed yarn guiding element and prior to said yarn heating means, a second movable yarn guiding element engaging the running yarn subsequent to said yarn heating means and prior to said second fixed yarn guiding element, and pattern control means operable upon said first and second movable yarn guiding elements.

3. In a knitting machine having a yarn supply, stitch forming means, a yarn feed finger, and yarn guiding means for directing a yarn from said yarn supply to said feed finger, the combination therewith of a yarn shrinking apparatus comprising a contact heater fixed on said knitting machine, fixed yarn guides adjacent opposite ends of said heater for normally guiding the running yarn in contact with said heater, movable yarn guides engaging the yarn between the fixed yarn guides and the heater for moving the yarn out of and into contact with the heater, and pattern control means operatively connected to said movable yarn guides.

4. In a structure according to claim 3 wherein said pattern control means comprises a thrust bar, a bell crank engaging said thrust bar, a Bowden wire connected at one end to said bell crank, a rigid portion connecting said first and second movable yarn guides, an arm fixed on said rigid portion and connected to said Bowden wire, a spring connected to said arm, said Bowden wire adapted to move said first and second movable yarn guides in one direction, and said spring adapted to move said first and second movable yarn guides in the opposite direction.

5. In a knitting machine having a yarn supply, stitch forming means, a yarn feed finger, and yarn guiding means for directing a yarn from said yarn supply to said feed finger, the combination therewith of a yarn shrinking apparatus comprising yarn heating means positioned adjacent thev path of the running yarn, and pattern controlled yarn guiding means operable to at times guide the running yarn into engagement with said yarn heating means to shrink the running yarn and to at other times guide said yarn out of engagement with said yarn heating means whereby the yarn will not be shrunk.

6. A yarn shrinking apparatus for a knitting machine having a yarn supply, stitch forming means, and yarn guiding means for directing a yarn from said yarn supply to said stitch forming means, said shrinking apparatus comprising yarn heating means disposed adjacent the path of the running yarn, and control means operable by said knitting machine to at times render said yarn heating means operative to shrink the running yarn and at other times to render said yarn heating means inoperative.

7. A yarn shrinking apparatus for a knitting machine having a yarn supply, stitch forming means, yarn guiding means for directing a yarn from said yarn supply to said stitch forming means, and yarn tension means between said supply means and said stitch forming means, said shrinking apparatus comprising yarn heating means disposed adjacent the path of the running yarn and between said yarn supply means and said stitch forming means, the temperature of said heating means being sufficient, and said heating means being operative, to shrink the running yarn prior to the formation of a knit fabric by said stitch forming means and control means operable by said knitting machine to at times render said yarn heating means operative to shrink the running yarn and at other times to render said yarn heating means inoperative.

8. A method of knitting womens seamless hosiery on a circular knitting machine having a yarn supply which comprises continuously feeding a heat-shrinkable thermoplastic yarn from said yarn supply to a heating means located between the yarn supply and the knitting needles, heating said yarn to at least partially plasticize it, and continuously knitting said yarn into fabric.

9. A method of knitting fabric on a knitting machine having a yarn supply which comprises feeding a thermoplastic yarn from said supply to a heating means located between the supply and the knitting needles, heating said yarn to at least partially plasticize it and knitting said yarn into fabric, the yarn being run as a continuous length from said supply to said knitting operation.

10. A method of knitting fabric on a knitting machine having a yarn supply which comprises feeding a thermoplastic yarn from said supply to a heating means located between the supply and the knitting needles, heating said yarn to shrink it and knitting said yarn into fabric, the yarn being run as a continuous length from said supply to said knitting operation.

References Cited in the file of this patent UNITED STATES PATENTS 2,247,716 Schellenberg et al July 1, 1941 2,396,166 Faucette Mar. 5, 1946 2,593,320 Lewis et al. Apr. 15, 1952 2,746,275 Cobert May 22, 1956 2,844,016 Cobert July 22, 1958 

8. A METHOD OF KNITTING WOMEN''S SEAMLESS HOSIERY ON A CIRCULAR KNITTING MACHINE HAVING A YARN SUPPLY WHICH COMPRISES CONTINUOUSLY FEEDING A HEAT-SHRINKABLE THERMOPLASTIC YARN FROM SAID YARN SUPPLY TO A HEATING MEANS LOCATED BETWEEN THE YARN SUPPLY AND THE KNITTING NEEDLES, HEATING SAID YARN TO AT LEAST PARTIALLY PLASTICIZE IT, AND CONTINUOUSLY KNITTING SAID YARN INTO FABRIC. 